Redoing Rusty Rockers

[FrustratedMunky]

Most of it, some of it is bubbling from under the paint so I'll have to see how severe it is once I get past the surface. If it's bubbling, would I still be able to get rid of the rust with the same procedure?

[AndrewBird]

Sounds good to me. I am assuming all you have is surface rust.

[FrustratedMunky]

I know this has been covered plenty of times but I want to make sure I get everything right. I'm planning on getting rid of all the rust on my rocker panels so here's the plan.

1. Wash rocker panels.
2. Sand rocker panels with low grit (80?) with sanding block until all rust is gone.
3. Rinse rocker panel off and dry.
4. Mask off rocker panel
4. Prep with primer on areas that have been stripped to bare metal.
5. Paint with rubberized paint.

Do I need to primer before painting with the rubberized paint? Or can I apply it right onto the metal?